1. Field
Example embodiments relate to an image sensor and manufacturing method thereof.
2. Description of the Related Art
Image sensors may include CMOS (complementary metal oxide semiconductor) type image sensors and CCD (charge coupled device) type image sensors. An image sensor may use a microlens to increase the amount of light input to a light receiving device and/or improve the efficiency in receiving light. As such, there has been an increase in the number of products (e.g., digital cameras) requiring image sensors.
FIG. 1 illustrates a conventional image sensor. Referring to FIG. 1, an image sensor 10 includes a plurality of photodiodes 100 and a plurality of microlenses 101. A plurality of principal rays 12 output from an external lens 11 is incident on a respective one of the microlenses 101 of the image sensor 10 at different incident angles.
The angles of the principal rays 12 incident on the photodiodes 100 in the image sensor 10 are different from one another. While almost vertical light (hereinafter the “vertical light”) is incident on a pixel (e.g., photodiode) located in the central area of the image sensor 10, the angle of each of the principal rays 12 incident on each pixel increases from the central area towards the edge of the image sensor 10.
As illustrated in circle X of FIG. 1, one of the principal rays 12 incident at an angle on a certain pixel is incident on at least one neighboring pixel, which causes reduced sensitivity of the image sensor and increased cross talk. As a result, the image sensor is directly affected by this phenomenon and the quality of an image produced by the image sensor is degraded and requires additional circuits to correct the quality of the image.
To solve the aforementioned problem, the position of the respective microlenses 101 may be relocated to the central area of the image sensor 10 or the height between each of the microlenses 101 and each of the photodiodes 100 may be decreased to reduce dependency upon the incident angle of the principal ray or light incident on each pixel. However, these methods may not be feasible solutions due to the complex structure and manufacturing process of the image sensor.